Hi, We have just moved into a new flat and I don't believe the off-peak heater is working on our PC125, but then again it could just be me not knowing how to use the boiler correctly. I would be grateful if someone can read the following and confirm if it is a likely fault with the boiler, in which case I will call out the Engineer;

Flat previously been unoccupied and boiler switched off for a couple of days, we moved in 1 week ago, not knowing much about this type of boiler we initially switched on both the peak & off-peak fused spur's at the wall;

Sunday - Switched on both the peak & off-peak fused spur's at the wall. I don't recall whether we had hot water or not during Sunday, we were not really home.

Monday morning - No hot water, Red trip switch went off overnight. Reading the boiler manual we reset the switch and using the Peak booster during Monday daytime we had hot water. Learnt at this point the peak booster should only be switched on for an hour or so, which we have been doing so since.

Monday eve - No hot water, trip switch off again so I reset. The LED display on circuit board is also sporadic, going from 'Normal' to 'T2 sensor' failure and occasionly indicating 'both sensor' failure.

Wednes morning - not hot water so I turned on the Peak booster for approx 20 minutes which just about provided sufficient (fluctuating hot/cold/) warm water for a quick shower. Later in the morning wife turned on booster for approx 1 hour which gave her a good shower, water temp. stopped fluctuating after approx 10 minutes to provide a prolonged, hot shower. No hot water by the evening.

Thurs & Fri mornings - Ditto Wednesday above.

My gut feeling is that we are now operating the boiler correctly (The off peak spur switched on all the time with the peak booster being switched on occasionly for max. 1 hour at a time) but the Off-Peak is not working as we dont have any hot water in the morning (6.00am), albeit the LED sensor is still displaying 'Normal' following the initial fluctuations earlier in the week.

Ok, we managed to locate the first problem; the previous tennant seems to have taken it upon himself to rewire the consumer unit! Now all the wires are back to the correct locations the off-peak boiler is working.

Another question; some mornings we have continuous hot water from the outset whereas other mornings we have Hot-Cold-Hot-Cold continuously, at least for the duration of my 10 minute or so shower. I understand the H-C-H-C fluctuation is a feature of the boiler for the initial few minutes but should the fluctuation really last for more than 10 minutes or is there another fault with the boiler?